Northampton captain Dylan Hartley admitted his side's display against Ulster "was not good enough" after slipping to a 25-6 defeat at Franklin's Gardens.
Comfortable cushion
Andrew Trimble and Tommy Bowe crossed in the first half to put the visitors 13-7 before a try from Jared Payne five minutes after the break opened up a comfortable cushion.
And despite flanker Iain Henderson being sin-binned with 10 minutes to go, Ulster grabbed a late bonus point when lock Dan Tuohy dived over in the right corner in the last minute.
"That was a bit of a statement," said coach Mark Anscombe.
"We weren't even thinking about the bonus point. We were more than happy to come here and take the win.
"We are not getting carried away. Northampton have too many quality players and they will bounce back from this performance.
"We have to go out and do it again next week or this will count for nothing."
The only disappointment for the Irish province was captain and second row Johan Muller forced off with what may possible be a broken arm.
